400amp Solinoid curiosity

[Fireball9298]

Everyone(dealers and forum people alike) recommended a 400amp solenoid paired with the XCT48500 controller, why not a 500amp like the controller? I'm baffled by this. Also one setting in the controller, Max motoring amature amps, im nervous to set it to the full 500amps bc of the 400amp solenoid. I'm nervous I'll hurt it. Can anyone please elaborate?

[Jake_Daddy]

That 400A solenoid will handle at least 2x that for short bursts and 400a continuously. You only use that many amps on takeoff or maybe climbing a steep mountain! My guess is even with some hills you don’t use much more that 100-200a while your rolling along and less than 80a on pavement. At continuous use 48v x 400a = 19,200 watts which converts to about 25hp. Even the alltrax won’t push 500a continuously its probably rated around 200-250 amps for continuous use.

[Sergio]

The main difference is that solenoids are rated at continuous current, the 400amp models will easily handle the alltrax 500 amps.

Just one note, the setting "Max motoring amature amps" is not the setting that controls the maximum current through the Solenoid, that is the max current in the Motor current circuit.

The setting "Max motoring Battery amps" setting is what controls the maximum current being pulled out of the battery pack and through the Solenoid.

You should set the battery amps setting to around 350-400 amps since the controller would still be able to generate twice that current at low speed through the motor circuit.

It will also help get better top speed since the greater the instantaneous take-off load current the longer it will take the pack voltage to recover from the initial voltage drop.

[Fireball9298]

Originally Posted by Jake_Daddy

That 400A solenoid will handle at least 2x that for short bursts and 400a continuously. You only use that many amps on takeoff or maybe climbing a steep mountain! My guess is even with some hills you don’t use much more that 100-200a while your rolling along and less than 80a on pavement. At continuous use 48v x 400a = 19,200 watts which converts to about 25hp. Even the alltrax won’t push 500a continuously its probably rated around 200-250 amps for continuous use.

Originally Posted by Sergio

The main difference is that solenoids are rated at continuous current, the 400amp models will easily handle the alltrax 500 amps.

Just one note, the setting "Max motoring amature amps" is not the setting that controls the maximum current through the Solenoid, that is the max current in the Motor current circuit.

The setting "Max motoring Battery amps" setting is what controls the maximum current being pulled out of the battery pack and through the Solenoid.

You should set the battery amps setting to around 350-400 amps since the controller would still be able to generate twice that current at low speed through the motor circuit.

It will also help get better top speed since the greater the instantaneous take-off load current the longer it will take the pack voltage to recover from the initial voltage drop.

That is gold advice right there! Right now I have it set to 500 on the battery, well thats the way the map came preset for user 2 on my Fnkey. It sure as hell throws me back hard but im only seeing 29mph on the big end. I'll tweak my setting down like you stated and see if the top end improves or at least gets to the same speed quicker.

Thank you both for the explanation, that makes perfect sense. i should have known. Its just like anything that electrical rated, home theatre amps, car amps, everything states continuous power and peak/spike power capable. Dont know why i didnt think of that. Thanks again guys!

[Fireball9298]

Originally Posted by Sergio

The main difference is that solenoids are rated at continuous current, the 400amp models will easily handle the alltrax 500 amps.

Just one note, the setting "Max motoring amature amps" is not the setting that controls the maximum current through the Solenoid, that is the max current in the Motor current circuit.

The setting "Max motoring Battery amps" setting is what controls the maximum current being pulled out of the battery pack and through the Solenoid.

You should set the battery amps setting to around 350-400 amps since the controller would still be able to generate twice that current at low speed through the motor circuit.

It will also help get better top speed since the greater the instantaneous take-off load current the longer it will take the pack voltage to recover from the initial voltage drop.

Another question for you though. On the max motoring amature amps, what does that actually affect? my field map came preset with that to 450amp. and battery amp preset to 500amp. I know you said it goes through the motor circuit but whats it affect?

[Sergio]

The settings you mentioned did not come with the Field Map, they were programmed by whoever sold you the cart.

The best way to visualize how those settings interact is to think of the Controller having to balance the power in two different systems, battery circuit and Motor Circuit.

The Sepex motor does not need much voltage at low speed, just current.

So the Controller can provide 400 amps @ 24v to the motor circuit (400A x 24V = 9,600 Watts) during take off while only using 200 amps on the 48v battery side ( 200A x 48V = 9,600Watts).

There are a few losses and other limiting factors so the conversion is not ideal from battery to motor, but it helps explain why battery current is not always the same as motor current.

It is also important to understand that just because the Motor consumes the current it does not mean it is actually using the current for Motoring, most of the excess current turns into heat in the motor.

Limiting the battery current to just before it noticeably affects performance and also reducing the throttle rate until it has a noticeable effect on performance will give you higher speeds and reduce heat in the Motor.

[Fireball9298]

Originally Posted by Sergio

The settings you mentioned did not come with the Field Map, they were programmed by whoever sold you the cart.

The best way to visualize how those settings interact is to think of the Controller having to balance the power in two different systems, battery circuit and Motor Circuit.

The Sepex motor does not need much voltage at low speed, just current.

So the Controller can provide 400 amps @ 24v to the motor circuit (400A x 24V = 9,600 Watts) during take off while only using 200 amps on the 48v battery side ( 200A x 48V = 9,600Watts).

There are a few losses and other limiting factors so the conversion is not ideal from battery to motor, but it helps explain why battery current is not always the same as motor current.

It is also important to understand that just because the Motor consumes the current it does not mean it is actually using the current for Motoring, most of the excess current turns into heat in the motor.

Limiting the battery current to just before it noticeably affects performance and also reducing the throttle rate until it has a noticeable effect on performance will give you higher speeds and reduce heat in the Motor.

Again, great info! I'm learning so much. Except I installed the XCT controller and Scotty loaded the bandit map for me before shipping. So those are the settings that were preloaded by the bandit field map unless I'm still not understanding how loading a field map works.

When field maps are loaded, is that not just changing the variables around that we can already adjust or is changing variables behind the scene that we can't even touch?

[Sergio]

I meant to say "Controller" instead of "Cart".

The only visible setting change is the "number of Poles", the other settings are the relation between Field current and Armature current which cannot be viewed or changed.

Anything else on those setting screens was changed and/or verified by the person that configured the Controller (not Alltrax either).

If You use the Alltrax log function during your test run You will see the difference in amps between Battery and Motor Armature as well as the direct impact that Battery current has on Battery voltage and how long it currently takes your pack to recover to the higher voltage.